RAID (Redundant Arrays of Independent Disks) may be an umbrella term for computer data storage schemes that divide and replicate data among multiple hard disk drives. RAID's various designs may balance or accentuate two key design goals: increased data reliability and increased I/O (input/output) performance. A number of standard schemes have evolved which are referred to as levels. There were five RAID levels originally conceived, but other variations have evolved.
A RAID (Redundant Arrays of Inexpensive Disks) level 3 algorithm uses byte-level striping with a dedicated parity disk. This mechanism provides an improved performance and fault tolerance (e.g., similar to RAID 5), but with the dedicated parity disk rather than rotated parity stripes. The dedicated parity disk (e.g., a single parity disk) can sometimes be a bottle-neck for writing since every write requires updating a parity data. A side-effect of RAID 3 is that it may not be able to service multiple requests simultaneously. Furthermore, the RAID 3 may be able to only recover up to one physical drive failure in one ‘data volume group’ (e.g., containing ‘n’ number of physical data drives and 1 drive for parity).